1. Field of the Invention
This invention relates to oil pressure shock absorbers and more particularly to an oil pressure shock absorber for absorbing a collision energy which is easy to make and assemble and is to be used to fit a bumper to an automobile.
2. Description of the Prior Art
Such oil pressure shock absorber can most effectively reduce shocks by uniformly absorbing a collision energy over the entire range of the stroke. However, as the operating velocity of the shock absorber is highest in the initial period of a collision and becomes zero in the end period, in order to obtain a uniform attenuating force over the entire range of the stroke from the initial period to the end period of the collision, it is necessary to gradually increase the oil flow resistance. Therefore, in the prior art, there has been taken such means as of gradually varying the depth of the oil flowing groove in the axial direction. However, such shock absorber has been complicated in the structure and very troublesome to make. Moreover, the prior shock absorber is difficult to be assembled and when it is once assembled, it is impossible to be disassembled and repaired, thus providing an uneconomical result.